WO2011065320A1 - Method for stopping indirect internal reforming type solid oxide fuel cell - Google Patents
Method for stopping indirect internal reforming type solid oxide fuel cell Download PDFInfo
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- WO2011065320A1 WO2011065320A1 PCT/JP2010/070774 JP2010070774W WO2011065320A1 WO 2011065320 A1 WO2011065320 A1 WO 2011065320A1 JP 2010070774 W JP2010070774 W JP 2010070774W WO 2011065320 A1 WO2011065320 A1 WO 2011065320A1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/06—Combination of fuel cells with means for production of reactants or for treatment of residues
- H01M8/0606—Combination of fuel cells with means for production of reactants or for treatment of residues with means for production of gaseous reactants
- H01M8/0612—Combination of fuel cells with means for production of reactants or for treatment of residues with means for production of gaseous reactants from carbon-containing material
- H01M8/0625—Combination of fuel cells with means for production of reactants or for treatment of residues with means for production of gaseous reactants from carbon-containing material in a modular combined reactor/fuel cell structure
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D7/00—Control of flow
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
- H01M8/04223—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids during start-up or shut-down; Depolarisation or activation, e.g. purging; Means for short-circuiting defective fuel cells
- H01M8/04228—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids during start-up or shut-down; Depolarisation or activation, e.g. purging; Means for short-circuiting defective fuel cells during shut-down
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
- H01M8/04298—Processes for controlling fuel cells or fuel cell systems
- H01M8/043—Processes for controlling fuel cells or fuel cell systems applied during specific periods
- H01M8/04303—Processes for controlling fuel cells or fuel cell systems applied during specific periods applied during shut-down
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
- H01M8/04298—Processes for controlling fuel cells or fuel cell systems
- H01M8/04313—Processes for controlling fuel cells or fuel cell systems characterised by the detection or assessment of variables; characterised by the detection or assessment of failure or abnormal function
- H01M8/0432—Temperature; Ambient temperature
- H01M8/04373—Temperature; Ambient temperature of auxiliary devices, e.g. reformers, compressors, burners
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
- H01M8/04298—Processes for controlling fuel cells or fuel cell systems
- H01M8/04694—Processes for controlling fuel cells or fuel cell systems characterised by variables to be controlled
- H01M8/04701—Temperature
- H01M8/04738—Temperature of auxiliary devices, e.g. reformer, compressor, burner
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
- H01M8/04298—Processes for controlling fuel cells or fuel cell systems
- H01M8/04694—Processes for controlling fuel cells or fuel cell systems characterised by variables to be controlled
- H01M8/04746—Pressure; Flow
- H01M8/04776—Pressure; Flow at auxiliary devices, e.g. reformer, compressor, burner
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/06—Combination of fuel cells with means for production of reactants or for treatment of residues
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/10—Fuel cells with solid electrolytes
- H01M8/12—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/24—Grouping of fuel cells, e.g. stacking of fuel cells
- H01M8/241—Grouping of fuel cells, e.g. stacking of fuel cells with solid or matrix-supported electrolytes
- H01M8/2425—High-temperature cells with solid electrolytes
- H01M8/243—Grouping of unit cells of tubular or cylindrical configuration
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/10—Fuel cells with solid electrolytes
- H01M8/12—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte
- H01M2008/1293—Fuel cells with solid oxide electrolytes
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
Definitions
- the present invention relates to a method for stopping an indirect internal reforming solid oxide fuel cell having a reformer in the vicinity of the fuel cell.
- Solid oxide electrolyte fuel cell Solid Oxide Fuel Cell
- SOFC Solid Oxide Fuel Cell
- SOFC is usually operated at a high temperature of 550-1000 ° C.
- SR steam reforming
- POX partial oxidation reforming
- ATR autothermal reforming
- Patent Document 2 If the method described in Patent Document 2 is used, it is considered that the anode can be held in a reducing atmosphere when the fuel cell is stopped, and oxidation deterioration of the anode can be prevented.
- An object of the present invention is to provide an indirect internal reforming SOFC capable of preventing the oxidative deterioration of the anode by the reformed gas while reliably reforming the hydrocarbon-based fuel, saving the fuel and shortening the time. Is to provide a stopping method.
- a reformer having a reforming catalyst layer for reforming hydrocarbon fuel to produce reformed gas; A solid oxide fuel cell that generates electric power using the reformed gas; and A combustion region for burning anode off-gas discharged from the solid oxide fuel cell;
- a method for stopping an indirect internal reforming solid oxide fuel cell comprising: a reformer, a solid oxide fuel cell, and a housing that houses a combustion region; The following conditions i to iv, i) The anode temperature of the solid oxide fuel cell is steady, ii) the anode temperature is below the oxidative degradation point; iii) In the reformer, the hydrocarbon-based fuel is reformed, and a reformed gas having a composition suitable for supplying to the anode is generated, iv) The amount of the reformed gas generated is equal to or higher than the minimum flow rate FrMin necessary for preventing the oxidative deterioration of the anode when the anode temperature of the solid oxide fuel cell is equal to or higher than
- FkE represents the flow rate of the hydrocarbon-based fuel supplied to the reformer in a state where all of the above are satisfied
- the flow rate of the hydrocarbon-based fuel that has been supplied to the reformer at the start of the stop method is expressed as Fk0
- FkCALC the calculated value of the flow rate of the hydrocarbon-based fuel that can be reformed by the type of reforming method performed after the start of the stopping method at the measured temperature of the reforming catalyst layer
- step C) a step of sequentially performing the following steps C1 to C5 when FkCALC ⁇ FkE in step A; C1) Reforming catalyst layer temperature T is measured, and FkCALC and flow rate FkMinCALC of a hydrocarbon-based fuel capable of generating a reformed gas having a flow rate of FrMin in the reformer are calculated using the measured temperature T. And comparing the values of FkMinCALC and FkE, C2) In step C1, when FkMinCALC ⁇ FkE, the flow rate of the hydrocarbon-based fuel supplied to the reformer is set to FkE, and the process proceeds to step D.
- step C3 a step of comparing the values of FkMinCALC and FkCALC calculated in step C1 when FkMinCALC ⁇ FkE in step C1;
- step C4 when FkCALC> FkMinCALC, the flow rate of the hydrocarbon-based fuel supplied to the reformer is changed to FkMINCALC, and the process returns to step C1.
- Step C5) A step of sequentially performing the following steps C6 to C9 when FkCALC ⁇ FkMinCALC in step C3, C6) raising the temperature of the reforming catalyst layer; C7) measuring the reforming catalyst layer temperature T, calculating FkCALC and FkMinCALC using the measured temperature T, and comparing the values of FkCALC and FkE; C8) When FkCALC ⁇ FkE in step C7, the flow rate of the hydrocarbon-based fuel supplied to the reformer is set to FkMinCALC, and the process returns to step C6.
- Step F7 in which, when FkCALC ⁇ FkE, the flow rate of the hydrocarbon-based fuel supplied to the reformer is set to FkE, and the process proceeds to Step D.
- a method for shutting down an indirect internal reforming solid oxide fuel cell is provided which comprises waiting for the anode temperature to fall below the oxidative degradation point.
- the hydrocarbon fuel may include a hydrocarbon fuel having 2 or more carbon atoms.
- the concentration of the compound having 2 or more carbon atoms in the reformed gas is preferably 50 ppb or less on a mass basis.
- the indirect internal reforming SOFC is stopped, which can prevent the oxidative deterioration of the anode by the reformed gas while reliably reforming the hydrocarbon-based fuel, and can save the fuel and shorten the time.
- a method is provided.
- “Steam / carbon ratio” or “S / C” refers to the ratio of the number of moles of water molecules to the number of moles of carbon atoms in the gas supplied to the reforming catalyst layer. “Oxygen / carbon ratio” or “O 2 / C” refers to the ratio of the number of moles of oxygen molecules to the number of moles of carbon atoms in the gas supplied to the reforming catalyst layer.
- FIG. 1 schematically shows an embodiment of an indirect internal reforming SOFC that can implement the present invention.
- the indirect internal reforming SOFC has a reformer 3 that reforms a hydrocarbon fuel to produce a reformed gas (hydrogen-containing gas).
- the reformer has a reforming catalyst layer 4.
- the indirect internal reforming SOFC has an SOFC 6 that generates electric power using the reformed gas, and also has a combustion region 5 in which anode off-gas discharged from the SOFC (particularly its anode) is combusted.
- the indirect internal reforming SOFC has a reformer, a solid oxide fuel cell, and a housing 8 that houses a combustion region.
- Indirect internal reforming SOFC refers to the housing (module container) 8 and the equipment contained therein.
- an igniter 7 that is an ignition means for igniting the anode off-gas is provided, and the reformer includes an electric heater 9.
- Each supply gas is preheated as necessary and then supplied to the reformer or SOFC.
- the indirect internal reforming SOFC is connected with a water vaporizer 1 equipped with an electric heater 2, and a pipe for supplying hydrocarbon fuel to the reformer is connected in the middle of the connecting pipe.
- the water vaporizer 1 generates water vapor by heating with the electric heater 2. Water vapor can be superheated appropriately in the water vaporizer or downstream thereof and then supplied to the reforming catalyst layer.
- air is also supplied to the reforming catalyst layer.
- air can be supplied to the reforming catalyst layer after preheating with a water vaporizer. Water vapor can be obtained from the water vaporizer, and a mixed gas of air and water vapor can be obtained.
- Hydrocarbon fuel is mixed with hydrocarbon fuel and supplied to the reformer 3, particularly the reforming catalyst layer 4.
- hydrocarbon-based fuel can be appropriately vaporized and then supplied to the reforming catalyst layer.
- the reformed gas obtained from the reformer is supplied to the SOFC 6, particularly the anode thereof. Although not shown, air is appropriately preheated and supplied to the SOFC cathode.
- the combustible component in the anode off gas (gas discharged from the anode) is burned by oxygen in the cathode off gas (gas discharged from the cathode) at the SOFC outlet.
- ignition can be performed using the igniter 7.
- the outlets of both the anode and the cathode are opened in the module container 8.
- the combustion gas is appropriately discharged from the module container.
- Reformer and SOFC are accommodated in one module container and modularized.
- the reformer is disposed at a position where heat can be received from the SOFC. For example, if the reformer is disposed at a position where it receives heat radiation from the SOFC, the reformer is heated by heat radiation from the SOFC during power generation.
- the reformer is preferably disposed at a position where radiation heat can be directly transferred from the SOFC to the outer surface of the reformer. Therefore, it is preferable that a shielding object is not substantially disposed between the reformer and the SOFC, that is, a gap is provided between the reformer and the SOFC. Further, it is preferable to shorten the distance between the reformer and the SOFC as much as possible.
- the reformer 3 is heated by the combustion heat of the anode off gas generated in the combustion region 5. Further, when the SOFC is at a higher temperature than the reformer, the reformer is also heated by radiant heat from the SOFC.
- the reformer may be heated by heat generated by reforming. If the reforming is partial oxidation reforming or autothermal reforming (autothermal reforming) and the heat generation by the partial oxidation reforming reaction is greater than the endothermic reaction by the steam reforming reaction, Fever accompanies.
- a state in which all of the following conditions i to iv are satisfied is referred to as a reforming stoppable state.
- the anode temperature of the SOFC is steady.
- the anode temperature is lower than the oxidation deterioration point.
- the hydrocarbon-based fuel is reformed, and a reformed gas having a composition suitable for supply to the anode is generated.
- the amount of the reformed gas generated is equal to or higher than the minimum flow rate FrMin necessary for preventing the oxidative deterioration of the anode when the anode temperature of the SOFC is equal to or higher than the oxidative deterioration point.
- the anode temperature means the temperature of the anode electrode.
- it can be the temperature of a stack component such as a separator in the vicinity of the anode.
- As the anode temperature measurement position it is preferable to adopt a location where the temperature is relatively high, more preferably a location where the temperature is highest, from the viewpoint of safety control.
- the position where the temperature rises can be known through preliminary experiments and simulations.
- the oxidation deterioration point is a temperature at which the anode is oxidized and deteriorated.
- the electrical conductivity of the anode material is measured by the direct current four-terminal method by changing the temperature in a reducing or oxidizing gas atmosphere, and in an oxidizing gas atmosphere.
- the minimum temperature at which the electrical conductivity at is lower than the value in the reducing gas atmosphere can be set as the oxidation deterioration point.
- the condition iii means that the hydrocarbon-based fuel is reformed in the reformer and a reformed gas having a composition suitable for supplying to the anode is obtained.
- the hydrocarbon-based fuel contains a hydrocarbon-based fuel having 2 or more carbon atoms
- the reformed gas is reducible, and the C2 + component (compound having 2 or more carbon atoms) in the reformed gas flows due to carbon deposition.
- the concentration of the C2 + component at this time is preferably 50 ppb or less as a mass fraction in the reformed gas.
- the minimum necessary reformed gas flow rate FrMin for preventing oxidative deterioration of the anode is the smallest flow rate among the flow rates at which the anode electrode is not oxidatively deteriorated due to diffusion of the cathode off-gas from the anode outlet to the inside of the anode.
- This reformed gas flow rate can be known in advance by performing experiments and simulations by changing the reformed gas flow rate while maintaining the anode temperature at or above the oxidation deterioration point.
- the anodic oxidation degradation can be judged by, for example, measuring the electrical conductivity of the anode electrode in an experiment and comparing it with an anode electrode that has not undergone oxidation degradation.
- the gas composition partial pressure of the anode can be calculated by simulation using an equation including an advection diffusion term, and can be determined by comparison with the equilibrium partial pressure in the oxidation reaction of the anode electrode.
- the equilibrium partial pressure of oxygen in the anode electrode oxidation reaction represented by the following formula is 1.2 ⁇ 10 ⁇ 14 atm (1.2 ⁇ 10 ⁇ 9 Pa) at 800 ° C.
- the calculated value of the oxygen partial pressure of the anode is smaller than this value, it can be determined that the anode electrode is not oxidized and deteriorated. Even when the anode temperature is other than 800 ° C., the maximum value of the oxygen partial pressure at which the anode electrode is not oxidized and deteriorated can be found by equilibrium calculation. If the calculated value of the oxygen partial pressure of the anode is smaller than that value, the anode electrode is oxidized. It can be judged that it does not deteriorate.
- the reformed gas flow rate (the amount of reformed gas generated by the reformer) supplied to the SOFC to prevent oxidative deterioration of the anode can be combusted when the reformed gas passes through the SOFC and is discharged from the anode.
- the flow rate is preferably as follows. When the smallest flow rate among the combustible reformed gas flow rates is larger than the above-mentioned minimum required reformed gas flow rate, the smallest flow rate among the combustible reformed gas flow rates is referred to as “required minimum flow rate” in the condition iv. Thus, the reformed gas flow rate can be obtained. Whether combustion is possible can be determined by, for example, sampling the gas in the combustion gas discharge line by experiment and performing composition analysis, or calculating by simulation.
- FkE can be obtained in advance by experiments or simulations.
- the flow rate of the fluid supplied to the indirect internal reforming SOFC such as the flow rate of the fluid such as water or air supplied to the heat exchanger; the reformer, the evaporator of water or liquid fuel, the SOFC, the fluid supply piping
- the electric input / output to the indirect internal reforming SOFC such as the electric heater output for heating etc., the electric input extracted from the thermoelectric conversion module, etc., is changed, that is, the operating conditions of the indirect internal reforming SOFC are changed.
- FkE can be known by conducting an experiment or simulation and searching for FkE that regularly satisfies the conditions i to iv.
- FkE may be any value as long as conditions i to iv are satisfied, but it is preferable to use the smallest FkE from the viewpoint of thermal efficiency.
- the operation condition of the indirect internal reforming SOFC including the FkE can be determined in advance as the operation condition in a state where the reforming can be stopped.
- [FkCALC] Calculation of the flow rate of the hydrocarbon-based fuel that can be reformed by the type of reforming method performed after the stop method is started at the measured reforming catalyst layer temperature (hereinafter, this flow rate is referred to as “reformable flow rate”).
- the value is expressed as FkCALC. That is, FkCALC can be obtained by measuring the temperature of the reforming catalyst layer and calculating the flow rate of the hydrocarbon-based fuel that can be reformed by the reforming catalyst layer when the reforming catalyst layer is at that temperature. it can.
- the reforming catalyst layer is subjected to the kind of reforming method performed after the start of the stop method (hereinafter, the type of reforming method is referred to as the reforming type).
- the reforming type is, for example, steam reforming, autothermal reforming, or partial oxidation reforming.
- the same type of reforming can be performed after the starting of the stopping method.
- the flow rate (calculated value) of the hydrocarbon-based fuel that can be reformed when the type of reforming is performed by the reformer is FkCALC.
- the flow rate of the hydrocarbon-based fuel that can be reformed at temperature is FkCALC.
- first type of reforming first type of reforming
- second type of reforming the flow rate of the hydrocarbon-based fuel that can be reformed when the second type reforming is performed by the reformer.
- FkCALC the flow rate of the hydrocarbon-based fuel that can be reformed when the second type reforming is performed by the reformer.
- the flow rate (calculated value) of the hydrocarbon-based fuel that can be reformed at the reforming catalyst layer measurement temperature is FkCALC.
- FkMinCALC A calculated value of the flow rate of the hydrocarbon-based fuel that can generate the reformed gas having the flow rate of FrMin by the reformer of the kind that is performed after the stop method is started at the measured reforming catalyst layer temperature is represented as FkMinCALC.
- FkMinCALC measures the temperature of the reforming catalyst layer, and when the reforming catalyst layer is at that temperature, the flow rate of the hydrocarbon-based fuel that can generate the reformed gas whose flow rate is FrMin in the reformer. It can be obtained by calculating. At this time, the reforming catalyst layer is subjected to the kind of reforming method performed after the stop method is started.
- reforming when changing the reforming method before and after the start of the stopping method.
- the same type of reforming may be performed before and after starting the stopping method, but different types of reforming may be performed.
- steam reforming can be performed before the stop method is started, and autothermal reforming can be performed after the stop method is started.
- steam reforming can be performed before the stop method is started, and partial oxidation reforming can be performed after the stop method is started.
- FkCALC and FkMinCALC are required to perform the reforming type after the reforming type change.
- the reforming stoppable state relates to the reforming type after the reforming type change. Therefore, FkE and FrMin are determined for the stoppable state when the reforming after the reforming type change is performed.
- the measured value of the reforming catalyst layer temperature is used.
- the reforming catalyst layer temperature is measured.
- the reforming catalyst layer temperature can be monitored (continuously measured).
- the temperature of the reforming catalyst layer is monitored before the start of the stop method, the temperature may be continuously monitored as it is.
- the temperature monitoring of the reforming catalyst layer may be continued until the anode temperature falls below the oxidation deterioration point.
- thermocouple An appropriate temperature sensor such as a thermocouple can be used for measuring the reforming catalyst layer temperature.
- Steps included in the stopping method In the present invention, the following steps A to D are performed while the anode temperature is not lower than the oxidation deterioration point. When the anode temperature falls below the oxidative degradation point, the supply of hydrocarbon fuel to the reformer can be stopped and the stopping method can be terminated regardless of the implementation status of Steps A to D.
- FIG. 6 is a flowchart showing steps A to D in the stopping method of the present invention.
- the anode temperature is monitored, and when the anode temperature falls below the oxidative deterioration point of the anode, the hydrocarbon fuel is supplied to the reformer regardless of the steps A to D. To stop.
- stopping method includes steps A to D, but it is not necessary to actually perform all of steps A to D, and some steps A to D may be performed depending on circumstances.
- step A if FkCALC ⁇ FkE, the following steps B1 to B4 are sequentially performed.
- FkCALC ⁇ FkE means that a hydrocarbon fuel having a flow rate of FkE cannot be reformed in the reformer (by changing the reforming type when the reforming type is changed). It is considered.
- step B1 is performed. That is, a step of raising the temperature of the reforming catalyst layer is performed.
- the temperature of the reforming catalyst layer is raised using an appropriate heat source such as a heater or a burner attached to the reformer.
- Process B2 And process B2 is performed. That is, a step of measuring the reforming catalyst layer temperature T, calculating FkCALC using this T, and comparing the values of FkCALC and FkE is performed.
- step B3 If FkCALC ⁇ FkE in step B2, a step returning to step B1 is performed. That is, steps B1 to B3 are repeated while FkCALC ⁇ FkE. During this time, the temperature of the reforming catalyst layer rises.
- step B1 In performing steps B2 and B3, the temperature increase in step B1 may be temporarily stopped, but step B1 may be continued while steps B2 and B3 are performed.
- step B4 If FkCALC ⁇ FkE in step B2, the flow rate of hydrocarbon-based fuel supplied to the reformer (represented as Fk) is changed from Fk0 to FkE, and the process proceeds to step D.
- FkCALC ⁇ FkE is considered to mean that a hydrocarbon-based fuel having a flow rate of FkE can be reformed in the reforming catalyst layer (depending on the reforming type after the change when the reforming type is changed).
- step C when FkCALC ⁇ FkE, step C is performed.
- FkCALC ⁇ FkE means that a hydrocarbon fuel with a flow rate of FkE can be reformed in the reformer (by changing the reforming type when the reforming type is changed before and after the start of the stop method). Consider it to mean.
- step C2 when FkMinCALC ⁇ FkE, the flow rate of the hydrocarbon-based fuel supplied to the reformer (Fk) is set to FkE, and the step of moving to step D is performed.
- the reformer When the reforming type is changed before and after the start of the stop method, when the process C2 is performed without performing the process C3, that is, when FkMinCALC ⁇ FkE is established in the first process C1, the reformer is supplied.
- the flow rate Fk of the hydrocarbon-based fuel is changed from Fk0 to FkE, the reforming type is changed, and the step of moving to step D is performed.
- step C4 when FkCALC> FkMinCALC, the flow rate Fk of the hydrocarbon-based fuel supplied to the reformer is set to FkMinCALC, and the process returns to step C1. That is, steps C1, C3, and C4 are repeated while FkMinCALC ⁇ FkE and FkCALC> FkMinCALC.
- the fuel flow rate Fk is changed from Fk0 to FkMinCALC in the first step C4 and the reforming type is changed.
- step C3 when FkCALC ⁇ FkMinCALC, steps C6 to C9 are sequentially performed.
- Step C6 The temperature of the reforming catalyst layer is raised. Step C6 can be performed in the same manner as Step B1.
- step C8 when FkCALK ⁇ FkE, the flow rate Fk of the hydrocarbon-based fuel supplied to the reformer is set to FkMinCALC (the value obtained in step C7), and the process returns to step C6.
- the fuel flow rate Fk is changed from Fk0 to FkMinCALC in the first process C8 and the reforming type is changed. To do.
- Step 7 when FkCALK ⁇ FkE, the flow rate Fk of the hydrocarbon-based fuel supplied to the reformer is set to FkE, and the process proceeds to Step D.
- Fk may be immediately changed to FkE, or Fk may be gradually changed to FkE (see case 3 described later).
- step D the process waits for the anode temperature to fall below the oxidation deterioration point. During this time, the flow rate of the hydrocarbon fuel is maintained at FkE, the flow rate of water for steam reforming or autothermal reforming (including steam) supplied to the reformer, air for autothermal reforming or partial oxidation reforming.
- the flow rate of the fluid supplied to the indirect internal reforming SOFC such as the flow rate, the cathode air flow rate, the fuel and air flow rate supplied to the burner, the flow rate of the fluid such as water and air supplied to the heat exchanger, the reformer and water Input and output of electricity to the indirect internal reforming SOFC, such as an electric heater output for heating an evaporator of liquid fuel, a cell stack, a fluid supply pipe, etc., an electric input taken from a thermoelectric conversion module, etc. It is possible to maintain the operation conditions in a predetermined reforming stoppable state. That is, it is possible to maintain the operation conditions of the indirect internal reforming SOFC in a predetermined reforming stoppable state. Since the anode temperature decreases with time, the anode temperature eventually falls below the oxidation degradation point. The anode temperature can be appropriately monitored (continuously measured) using a temperature sensor such as a thermocouple.
- the monitoring of the anode temperature is preferably started immediately after the stop method is started. If these temperatures are monitored before the stop method is started, the temperature may be continuously monitored even when the stop method is performed.
- the supply of hydrocarbon fuel to the reformer can be stopped to end the stopping method.
- a hydrocarbon-based fuel having a flow rate capable of generating a reformed gas having a flow rate of FrMin is reformable, and the hydrocarbon-based fuel having the flow rate is supplied to the reformer.
- the fuel supply flow rate Fk to the reformer is FkE (the operation condition is the operation condition in which the reforming can be stopped)
- the unreformed hydrocarbon fuel does not flow into the anode.
- the reforming gas flow rate is larger as the reforming catalyst layer temperature is higher in a temperature range preferable for reforming.
- the flow rate of the hydrocarbon fuel that can generate the reformed gas having the flow rate of FrMin in the reformer is smaller than FkE. Therefore, if Fk is set to FkE, excess hydrocarbon fuel is consumed. In general, the more hydrocarbon fuel to be supplied, the more time is required for cooling.
- step C the hydrocarbon fuel can be suppressed to the minimum necessary by supplying the reformer with hydrocarbon fuel having a flow rate of FkMinCALC.
- FkCALC ⁇ FkMinCALC may be satisfied due to a decrease in the reforming catalyst layer temperature.
- FkCALC ⁇ FkMinCALC if FkE ⁇ FkCALC, the fuel flow rate Fk is set to FkE (the operating condition is the operating condition in a state where the reforming can be stopped), and the unreformed hydrocarbon fuel is not allowed to flow into the anode. It is possible to shift to a state where reforming can be stopped.
- step C2 when FkMinCALC ⁇ FkE, the fuel flow rate Fk is set to FkE (the operation condition is set to the operation condition in which the reforming can be stopped) (step C2), thereby suppressing the hydrocarbon-based fuel supplied to the reformer.
- the unreformed hydrocarbon fuel can be shifted to the state where the reforming can be stopped without flowing into the anode.
- step C5 the unreformed hydrocarbon fuel can be shifted to a state where the reforming can be stopped without flowing into the anode.
- the horizontal axis represents the elapsed time from the start of the stopping method of the present invention.
- the vertical axis represents the flow rate of reformed gas obtained from the reformer
- the vertical axis represents temperature
- the vertical axis represents the flow rate of hydrocarbon fuel (reformation).
- the flow rate Fk of hydrocarbon-based fuel supplied to the vessel, the calculated FkCALC and FkMINCALC) (the same applies to FIGS. 3 to 5).
- the monitoring of the reforming catalyst layer temperature and the monitoring of the anode temperature are continued from before the start of the stopping method (the same applies to the following cases).
- step A is performed immediately after starting the stopping method. That is, the reforming catalyst layer temperature T is measured, FkCALC is calculated using this T, and the values of FkCALC and FkE are compared.
- Step C is performed.
- step C1 the reforming catalyst layer temperature T is measured, FkMinCALC and FkCALC are calculated based on this T, and the values of FkMinCALC and FkE are compared.
- step C3 is performed instead of step C2.
- step C3 the values of FkMinCALC and FkCALC calculated in step C1 are compared.
- Step C4 the flow rate of the hydrocarbon-based fuel supplied to the reformer is changed to FkMINCALC, and the process returns to Step C1.
- the flow rate of the hydrocarbon-based fuel is changed from Fk0 to FkMinCALC in the first step C4 and the reforming type is changed.
- Steps C1, C3, and C4 are repeated while FkCALC> FkMinCALC. Steps C1, C3, and C4 are repeated for a while, while the reforming catalyst layer temperature decreases with time, FkMinCALC increases with time, and FkCALC decreases with time.
- FkCALC becomes FkMinCALC or less earlier than FkMINCALC becomes FkE or more.
- Step C5 is performed. That is, steps C6 to C9 are sequentially performed.
- step C6 the temperature of the reforming catalyst layer is raised.
- the temperature increase in the step 6 is performed in order to raise the reforming catalyst layer temperature so that the hydrocarbon fuel at the flow rate FkE can be reformed.
- the temperature of the reforming catalyst layer can be raised with an appropriate heat source such as a burner or a heater attached to the reformer until FkCALC ⁇ FkE.
- step C7 the reforming catalyst layer temperature T is measured, and FkCALC and FkMinCALC are obtained using this T, and the obtained FkCALC value is compared with the FkE value.
- Step C8 the flow rate (Fk) of the hydrocarbon-based fuel supplied to the reformer is set to FkMinCALC obtained in Step C7, and the process returns to Step C6.
- Steps C6, C7 and C8 are repeated (the temperature of step C6 may be continued during this time), and the temperature of the reforming catalyst layer increases with time, FkMinCALC decreases, and FkCALC increases I will do it.
- FkCALC becomes equal to or lower than FkMALCALC
- the flow rate of the hydrocarbon fuel is FkMINCALC until FkCALC ⁇ FkE. Therefore, in FIG. 2C, the line representing FkMinCALC and the line representing Fk overlap during this period.
- the flow rate (Fk) of the hydrocarbon-based fuel supplied to the reformer is set to FkE (step C9).
- the operation conditions in the reforming stoppable state can be set, including other operation conditions of the indirect internal reforming SOFC.
- step D the process proceeds to step D and waits until the anode temperature falls below the oxidation deterioration point.
- the flow rate of the hydrocarbon-based fuel supplied to the reformer can be made zero, and the stopping method can be finished.
- the flow rate of the hydrocarbon fuel can be made zero at that point.
- FkMALCALC becomes FkE or higher sooner than FkCALC becomes FkMINCALC or lower.
- FkMinCALC becomes equal to or higher than FkE
- Fk is set to FkE, and the process proceeds to Step D (Step C2).
- the operation conditions in the reforming stoppable state can be set, including other operation conditions of the indirect internal reforming SOFC.
- step C5 steps C6 to C9 is not performed (step B is not performed).
- the flow rate of the hydrocarbon fuel can be made zero at that point.
- Fk is first increased to FkM in Step C9.
- FkM is an intermediate flow rate that is larger than FkMinCALC and smaller than FkE.
- FkCALC ⁇ FkE When FkCALC ⁇ FkE is satisfied at the time (Jth), Fk can be set to FkE. At this time, other operation conditions can be set to the operation conditions in the reforming stoppable state. Thereafter, the supply of hydrocarbon fuel to the reformer may be stopped after waiting until the anode temperature becomes lower than the oxidation deterioration point. The calculation of FkCALC may be terminated when FkCALC ⁇ FkE is satisfied in the last round.
- the temperature of the reforming catalyst layer is increased from the time when FkCALC ⁇ FkE in step C7 (when Fk is set to FkM (1)) and the time when FkCALC ⁇ FkE is reached in the last round (Fk is changed to FkE) It is also possible to end the process before
- the intermediate flow rate FkM (j) can be determined, for example, by calculating the flow rate obtained by dividing Jk + 1 between FkMINCALC and FkE when FkCALC ⁇ FkE in Step C7. However, it is better to increase J as much as possible and decrease the interval of FkM (j) within the allowable range of memory consumption of the flow rate control means and within the range exceeding the accuracy of the boosting means and flow rate control / measurement means. It is preferable from the viewpoint of reducing the integrated flow rate of hydrocarbon-based fuel, that is, thermal efficiency.
- Case 3 can reduce the amount of hydrocarbon fuel to be supplied before the reforming stop, and the stop time, compared to Case 1.
- Step A is performed immediately after the stop method is started, and the reforming catalyst layer temperature T is measured and FkCALC is calculated based on this T. Since FkCALC ⁇ FkE, step B is not performed but step B is performed.
- the reforming catalyst layer is formed with an appropriate heat source such as a burner or a heater attached to the reformer until FkCALC ⁇ FkE so that the hydrocarbon-based fuel having a flow rate FkE can be reformed. Raise the temperature. Specifically, the temperature of the reforming catalyst layer is raised in step B1. In step B2, the reforming catalyst layer temperature T is measured, FkCALC is calculated using this T, and the value of FkCALC is compared with the value of FkE. If FkCALC ⁇ FkE, the process returns to step B1. Steps B1, B2, and B3 are repeated while FkCALC ⁇ FkE (during this time, the temperature increase in step B1 may be continued).
- an appropriate heat source such as a burner or a heater
- a hydrocarbon-based fuel at a certain flow rate in the reforming catalyst layer can be reformed means that when the hydrocarbon-based fuel at that flow rate is supplied to the reforming catalyst layer, it is discharged from the reforming catalyst layer.
- the composition of the gas to be used is a composition suitable for supplying to the anode of the SOFC.
- being able to be reformed in the reforming catalyst layer means that the supplied hydrocarbon fuel can be decomposed to a C1 compound (a compound having 1 carbon atom). That is, the reforming catalyst layer is modified until the C2 + component (the component having 2 or more carbon atoms) in the reforming catalyst layer outlet gas has a concentration that does not cause a problem with respect to channel blockage or anode deterioration due to carbon deposition. It means a case where quality can progress.
- the concentration of the C2 + component at this time is preferably 50 ppb or less as a mass fraction in the reformed gas.
- the reforming catalyst layer outlet gas only needs to be reducible. It is allowed that methane is contained in the reforming catalyst layer outlet gas.
- methane In the reforming of hydrocarbon-based fuels, methane usually remains in equilibrium. Even when the reforming catalyst layer outlet gas contains carbon in the form of methane, CO, or CO 2 , carbon deposition can be prevented by adding steam as necessary. When methane is used as the hydrocarbon-based fuel, reforming may be advanced so that the reforming catalyst layer outlet gas becomes reducible.
- the partial pressure of oxidizing O 2 , H 2 O, CO 2 and the like contained in the reforming catalyst layer outlet gas can be made lower than the equilibrium partial pressure in the oxidation reaction of the anode electrode.
- the O 2 partial pressure contained in the reforming catalyst layer outlet gas is less than 1.2 ⁇ 10 ⁇ 14 atm (1.2 ⁇ 10 ⁇ 9 Pa) , less than 1.7 ⁇ 10 2 partial pressure ratio of H 2 O for H 2, the partial pressure ratio of CO 2 to CO may be less than 1.8 ⁇ 10 2.
- reformability is as described above, and the flow rate of the hydrocarbon-based fuel that can be reformed in the reforming catalyst layer (reformable flow rate) is the same as that of the hydrocarbon-based fuel at the flow rate. Is a flow rate at which the composition of the gas discharged from the reforming catalyst layer becomes a composition suitable for supplying to the anode of the SOFC.
- the reformable flow rate in the reforming catalyst layer can be an arbitrary flow rate that is not more than the maximum value of the flow rate at which the supplied hydrocarbon fuel can be decomposed to the C1 compound (compound having 1 carbon atom).
- the reformable flow rate can be the maximum value, or can be a value obtained by dividing the maximum value by a safety factor (a value exceeding 1; for example, 1.4).
- the reformable flow rate depends on the temperature of the reforming catalyst layer. Therefore, calculation of the reformable flow rate in the reforming catalyst layer is performed based on the measured temperature of the reforming catalyst layer.
- the reformable flow rate FkCALC in the reforming catalyst layer can be obtained by an experiment in advance as a function of the temperature T of the reforming catalyst layer (represented as FkCALC (T) when explicitly indicating that the function is a function of temperature). .
- FkCALC (T) when explicitly indicating that the function is a function of temperature.
- the unit of FkCALC (T) is, for example, mol / s.
- the reformable flow rate FkCALC (T) can be a function of temperature T only.
- the reformable flow rate FkCALC may be a function having a variable other than T such as the catalyst layer volume, the concentration of the gas component, and the time in addition to the temperature T.
- a variable other than T is appropriately obtained, and the reformable flow rate FkCALC (T) is calculated from the variable other than T and the measured T. Can do.
- the flow rate of the hydrocarbon-based fuel that can generate the reformed gas having a flow rate of FrMin in the reformer can be any flow rate that is equal to or higher than the flow rate at which the flow rate of the reformed gas is just FrMin.
- the flow rate of the hydrocarbon fuel that can generate the reformed gas with the flow rate of FrMin can be set to the flow rate of the hydrocarbon fuel that can generate the reformed gas with the flow rate of FrMin with the reformer.
- the flow rate can be a value obtained by multiplying the flow rate by a safety factor (a value exceeding 1; for example, 1.4).
- FkMinCALC depends on the temperature of the reforming catalyst layer. Therefore, FkMinCALC is performed based on the measured temperature of the reforming catalyst layer.
- FkMinCALC can be calculated by knowing the relational expression of the reforming catalyst layer and FkMinCALC in advance by equilibrium calculation or preliminary experiment, and substituting the measured temperature T of the reforming catalyst layer into the relational expression. Further, FkMinCALC can be obtained after multiplying a function obtained by experiment by a safety factor or correcting the temperature on the safe side.
- the unit of FkMinCALC is, for example, mol / s.
- FkMinCALC can be a function of temperature T only.
- FkMinCALC may be a function having variables other than T such as pressure, gas component concentration, time, etc. in addition to temperature T.
- a variable other than T can be obtained as appropriate, and FkMinCALC can be calculated from the variable other than T and the measured T.
- the temperature measurement location is preferably a location where the temperature is relatively low in the reforming catalyst layer, from the viewpoint of safety side control, More preferably, it is preferable to employ a portion having the lowest temperature in the reforming catalyst layer.
- the heat of reaction in the reforming catalyst layer is endothermic, the vicinity of the center of the catalyst layer can be selected as the temperature measurement location.
- the heat of reaction in the reforming catalyst layer is exothermic, and the end portion becomes cooler than the center portion due to heat dissipation, the end portion of the catalyst layer can be selected as the temperature measurement location.
- the position where the temperature is lowered can be known by preliminary experiments and simulations.
- the temperature measurement point need not be a single point. From the viewpoint of more accurate control, it is preferable that there are two or more temperature measurement points. For example, the inlet temperature and outlet temperature of the reforming catalyst layer are measured, and the average of these can be used as the aforementioned reforming catalyst layer temperature T.
- the reaction rate other than the reaction accompanied by a decrease in the hydrocarbon fuel (raw fuel) supplied to the reforming catalyst layer is much faster than the reaction accompanied by the decrease in the raw fuel, and components other than the raw fuel instantaneously have an equilibrium composition.
- the temperature at which FkMinCALC is calculated in Step C is the highest at the reforming catalyst layer outlet among the temperatures measured at the plurality of points. It is preferable to use close temperatures. In the case where there are a plurality of temperatures closest to the reforming catalyst layer outlet, appropriately calculated values such as the lowest value and the average value thereof can be used as representative values.
- the reforming catalyst layer to N divided regions Z i (N is an integer of 2 or more, i is an integer 1 or more N) thinking, knowing the temperature T i of each divided region Z i, the temperature T i From which FkCALC and FkMINCALC can be calculated.
- FkCALC and FkMINCALC may be calculated for all divided regions, or values calculated for only some of the divided regions of N divided regions may be FkCALC, and You may employ
- the catalyst layer region to be calculated can be appropriately changed according to the hydrocarbon fuel supply amount.
- the actually measured temperature can be used as it is, but an appropriately calculated value such as an average value of the inlet temperature and the outlet temperature of the divided region can also be used as a representative value.
- the catalyst layer division number N and the number of temperature measurement points can be set independently.
- the temperature of the divided area closest to the divided area can be used.
- the temperature of one of the two divided regions can be used, or the average value of the temperatures of the two divided regions can be used.
- the temperature of a plurality of reforming catalyst layers can be measured, and the temperature of each divided area can be known from the measured temperatures of the plurality of points. For example, the temperature at the inlet and outlet of the reforming catalyst layer is measured (and the temperature at an arbitrary position in the middle portion may be measured), and the reforming catalyst layer is measured from these measured temperatures by an approximation method such as the least square method. It is possible to interpolate the temperature and know the temperature of the divided area from the interpolation curve.
- FkCALC and FkMinCALC may be calculated using the temperatures at the same location in each step. Or you may perform calculation of FkCALC and calculation of FkMinCALC using the temperature of a different location.
- Example of temperature measurement location In order to know the temperature of all the divided areas, the temperature of the following points can be measured. -Entrance and exit of each divided area. -Inside each divided area (inside from the entrance and exit) (one or more points). -Entrance, exit and inside of each divided area (one or more points for one divided area).
- the temperature at the following locations can be measured. -Entrance and exit of some divided areas. -Inside of some divided areas (inside from the inlet and outlet) (one or more points). -Entrances, exits, and interiors of some divided areas (one or more points for one divided area).
- the reforming type When changing Fk to a value other than FkE, for example, when changing the flow rate of hydrocarbon fuel supplied to the reformer in the steps C4 and C8 or the step of changing Fk to FkM in step C9, the reforming type
- the flow rate of the fluid supplied to the indirect internal reforming SOFC and the input / output of electricity to the indirect internal reforming SOFC are set to predetermined operating conditions. can do.
- the flow rate of water supplied to the reformer is set to a fixed value such as a predetermined operation condition in a state where reforming can be stopped, or the steam / carbon ratio is maintained at a predetermined value in order to suppress carbon deposition.
- the water flow rate can be changed with the change of the fuel flow rate.
- the air flow rate supplied to the reformer can be changed with the change of the fuel flow rate so that the oxygen / carbon ratio maintains a predetermined value.
- operation in a predetermined reforming stoppable state It can be a fixed value such as a condition or can be a predetermined operating condition as a function of the fuel flow rate.
- the present invention is particularly effective when the hydrocarbon fuel has 2 or more carbon atoms. This is because such fuel is particularly required to be reformed.
- an appropriate instrumentation control device including a computing means such as a computer can be used.
- hydrocarbon fuel As the hydrocarbon-based fuel, as a reformed gas raw material, a compound known from the field of SOFC, containing carbon and hydrogen (may contain other elements such as oxygen) or a mixture thereof, or a mixture thereof may be used as appropriate. And compounds having carbon and hydrogen in the molecule such as hydrocarbons and alcohols can be used.
- hydrocarbon fuel such as methane, ethane, propane, butane, natural gas, LPG (liquefied petroleum gas), city gas, gasoline, naphtha, kerosene, light oil, etc., alcohol such as methanol and ethanol, ether such as dimethyl ether, etc. is there.
- kerosene and LPG are preferred because they are readily available. Moreover, since it can be stored independently, it is useful in areas where city gas lines are not widespread. Furthermore, SOFC power generators using kerosene or LPG are useful as emergency power supplies. In particular, kerosene is preferable because it is easy to handle.
- the reformer produces a reformed gas containing hydrogen from a hydrocarbon fuel.
- any of steam reforming, partial oxidation reforming, and autothermal reforming accompanied by a partial oxidation reaction in the steam reforming reaction can be performed.
- the reformer is appropriately equipped with a steam reforming catalyst having steam reforming ability, a partial oxidation reforming catalyst having partial oxidation reforming ability, and a self-thermal reforming catalyst having both partial oxidation reforming ability and steam reforming ability. Can be used.
- a structure known as a reformer can be appropriately adopted.
- a structure having a region for accommodating the reforming catalyst in a sealable container and having an inlet for fluid necessary for reforming and an outlet for reforming gas can be appropriately adopted.
- the material of the reformer can be appropriately selected and adopted from materials known as reformers in consideration of resistance in the use environment.
- the shape of the reformer can be an appropriate shape such as a rectangular parallelepiped or a circular tube.
- the reformed gas obtained from the reformer is supplied to the anode of the SOFC.
- an oxygen-containing gas such as air is supplied to the cathode of the SOFC.
- the SOFC generates heat with power generation, and the heat is transmitted from the SOFC to the reformer by radiant heat transfer or the like.
- the SOFC exhaust heat is used to heat the reformer. Gas exchange and the like are appropriately performed using piping or the like.
- SOFC a known SOFC can be selected and adopted as appropriate.
- oxygen ion conductive ceramics or proton ion conductive ceramics are generally used as an electrolyte.
- the SOFC may be a single cell, but in practice, a stack in which a plurality of single cells are arranged (in the case of a cylindrical type, sometimes referred to as a bundle, but the stack in this specification includes a bundle) is preferable. Used. In this case, one or more stacks may be used.
- the shape of the SOFC is not limited to the cubic stack, and an appropriate shape can be adopted.
- oxidation deterioration of the anode may occur at about 400 ° C.
- an appropriate container capable of accommodating the SOFC, the reformer, and the combustion region can be used.
- the material for example, an appropriate material having resistance to the environment to be used, such as stainless steel, can be used.
- the container is appropriately provided with a connection port for gas exchange and the like.
- the module container has airtightness so that the inside of the module container and the outside (atmosphere) do not communicate with each other.
- the combustion region is a region where the anode off gas discharged from the anode of the SOFC can be combusted.
- the anode outlet can be opened in the housing, and the space near the anode outlet can be used as a combustion region.
- This combustion can be performed using, for example, a cathode off gas as the oxygen-containing gas.
- the cathode outlet can be opened in the housing.
- An ignition means such as an igniter can be appropriately used to burn the combustion fuel or anode off gas.
- Any of the steam reforming catalyst, partial oxidation reforming catalyst, and autothermal reforming catalyst used in the reformer can be a known catalyst.
- the steam reforming catalyst include ruthenium-based and nickel-based catalysts
- examples of the partial oxidation reforming catalyst include platinum-based catalysts
- examples of the autothermal reforming catalyst include rhodium-based catalysts.
- a self-thermal reforming catalyst having a steam reforming function can also be used.
- the temperature at which the partial oxidation reforming reaction can proceed is, for example, 200 ° C. or more, and the temperature at which the steam reforming reaction or autothermal reforming reaction can proceed is, for example, 400 ° C. or more.
- steam reforming steam is added to reforming raw materials such as kerosene.
- the reaction temperature of the steam reforming can be performed, for example, in the range of 400 ° C. to 1000 ° C., preferably 500 ° C. to 850 ° C., more preferably 550 ° C. to 800 ° C.
- the amount of steam introduced into the reaction system is defined as the ratio of the number of moles of water molecules to the number of moles of carbon atoms contained in the hydrocarbon fuel (steam / carbon ratio), and this value is preferably 1 to 10, more preferably It is 1.5-7, more preferably 2-5.
- the space velocity (LHSV) at this time is A / B when the flow rate in the liquid state of the hydrocarbon fuel is A (L / h) and the catalyst layer volume is B (L).
- This value is preferably set in the range of 0.05 to 20 h ⁇ 1 , more preferably 0.1 to 10 h ⁇ 1 , still more preferably 0.2 to 5 h ⁇ 1 .
- an oxygen-containing gas is added to the reforming raw material in addition to steam.
- the oxygen-containing gas may be pure oxygen, but air is preferred because of its availability. Equilibrium calculations can be performed and an oxygen-containing gas can be added so that the overall reaction heat is exothermic.
- the addition amount of the oxygen-containing gas is preferably 0.005 to 1, more preferably 0.01 to 0.00 as the ratio of the number of moles of oxygen molecules to the number of moles of carbon atoms contained in the hydrocarbon fuel (oxygen / carbon ratio). 75, more preferably 0.02 to 0.6.
- the reaction temperature of the autothermal reforming reaction is set, for example, in the range of 400 ° C. to 1000 ° C., preferably 450 ° C.
- the space velocity (LHSV) at this time is preferably 0.05 to 20 h ⁇ 1 , more preferably 0.1 to 10 h ⁇ 1 , further preferably 0.2 to 5 h ⁇ 1. Is selected within the range.
- the amount of steam introduced into the reaction system is preferably 1 to 10, more preferably 1.5 to 7, and still more preferably 2 to 5 as a steam / carbon ratio.
- an oxygen-containing gas is added to the reforming raw material.
- the oxygen-containing gas may be pure oxygen, but air is preferred because of its availability.
- the amount added is appropriately determined in terms of heat loss and the like.
- the amount is preferably 0.1 to 3, more preferably 0.2 to 0.7, as the ratio of the number of moles of oxygen molecules to the number of moles of carbon atoms contained in the hydrocarbon fuel (oxygen / carbon ratio).
- the reaction temperature of the partial oxidation reaction can be set, for example, in the range of 450 ° C. to 1000 ° C., preferably 500 ° C. to 850 ° C., more preferably 550 ° C. to 800 ° C.
- the space velocity (LHSV) at this time is preferably selected in the range of 0.1 to 30 h ⁇ 1 .
- steam can be introduced, and the amount thereof is preferably 0.1 to 5, more preferably 0.1 to 3, more preferably 1 to 3 as the steam / carbon ratio. 2.
- Known components of the indirect internal reforming SOFC can be appropriately provided as necessary.
- Specific examples include a vaporizer for vaporizing liquid, a pump for pressurizing various fluids, a pressure increasing means such as a compressor and a blower, a valve for adjusting the flow rate of the fluid, or for blocking / switching the flow of the fluid.
- the present invention can be applied to an indirect internal reforming SOFC used for, for example, a stationary or moving power generator or a cogeneration system.
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Abstract
Description
炭化水素系燃料を改質して改質ガスを製造する、改質触媒層を有する改質器と、
該改質ガスを用いて発電を行う固体酸化物形燃料電池と、
該固体酸化物燃料電池から排出されるアノードオフガスを燃焼させる燃焼領域と、
該改質器、固体酸化物形燃料電池および燃焼領域を収容する筐体と、を有する間接内部改質型固体酸化物形燃料電池の停止方法であって、
次の条件iからiv、
i)該固体酸化物燃料電池のアノード温度が定常であり、
ii)該アノード温度が酸化劣化点未満であり、
iii)改質器において、炭化水素系燃料が改質され、アノードに供給するのに適した組成の改質ガスが生成しており、
iv)前記改質ガスの生成量が、該固体酸化物燃料電池のアノード温度が酸化劣化点以上の温度にある場合においてアノードの酸化劣化を防止するために必要最小限な流量FrMin以上である、
が全て満たされる状態において改質器に供給される炭化水素系燃料の流量をFkEと表し、
停止方法開始時点で改質器に供給していた炭化水素系燃料の流量をFk0と表し、
測定された改質触媒層の温度において、停止方法開始後に行う種類の改質法により改質可能な炭化水素系燃料の流量の計算値をFkCALCと表したとき、
アノード温度が酸化劣化点を下回ったら改質器への炭化水素系燃料の供給を停止して該停止方法を終了し、
アノード温度が酸化劣化点を下回っていない間に以下の工程、
A)改質触媒層温度Tを測定し、この測定温度Tを用いてFkCALCを算出し、このFkCALCとFkEの値を比較する工程、
B)工程AにおいてFkCALC<FkEの場合に、次の工程B1~B4を順次行なう工程、
B1)改質触媒層を昇温する工程、
B2)改質触媒層温度Tを測定し、この測定温度Tを用いてFkCALCを算出し、このFkCALCとFkEの値を比較する工程、
B3)工程B2においてFkCALC<FkEの場合に、工程B1に戻る工程、
B4)工程B2においてFkCALC≧FkEの場合に、改質器に供給する炭化水素系燃料の流量をFk0からFkEにし、工程Dに移る工程、
C)工程AにおいてFkCALC≧FkEの場合に、次の工程C1~C5を順次行なう工程、
C1)改質触媒層温度Tを測定し、この測定温度Tを用いて、FkCALCと、流量がFrMinである改質ガスを改質器で生成可能な炭化水素系燃料の流量FkMinCALCと、を算出し、このFkMinCALCとFkEとの値を比較する工程、
C2)工程C1において、FkMinCALC≧FkEの場合に、改質器に供給する炭化水素系燃料の流量をFkEにし、工程Dに移る工程、
C3)工程C1においてFkMinCALC<FkEの場合に、工程C1で算出したFkMinCALCとFkCALCとの値を比較する工程、
C4)工程C3において、FkCALC>FkMinCALCの場合に、改質器に供給する炭化水素系燃料の流量をFkMinCALCにし、工程C1に戻る工程、
C5)工程C3において、FkCALC≦FkMinCALCの場合に、次の工程C6~C9を順次行う工程、
C6)改質触媒層を昇温する工程、
C7)改質触媒層温度Tを測定し、この測定温度Tを用いてFkCALCおよびFkMinCALCを算出し、このFkCALCとFkEの値を比較する工程、
C8)工程C7においてFkCALC<FkEの場合に、改質器に供給する炭化水素系燃料の流量をFkMinCALCにし、工程C6に戻る工程、
C9)工程C7においてFkCALC≧FkEの場合に、改質器に供給する炭化水素系燃料の流量をFkEにし、工程Dに移る工程、
および
D)アノード温度が、酸化劣化点を下回るのを待つ工程
を有する間接内部改質型固体酸化物形燃料電池の停止方法が提供される。 According to the present invention,
A reformer having a reforming catalyst layer for reforming hydrocarbon fuel to produce reformed gas;
A solid oxide fuel cell that generates electric power using the reformed gas; and
A combustion region for burning anode off-gas discharged from the solid oxide fuel cell;
A method for stopping an indirect internal reforming solid oxide fuel cell comprising: a reformer, a solid oxide fuel cell, and a housing that houses a combustion region;
The following conditions i to iv,
i) The anode temperature of the solid oxide fuel cell is steady,
ii) the anode temperature is below the oxidative degradation point;
iii) In the reformer, the hydrocarbon-based fuel is reformed, and a reformed gas having a composition suitable for supplying to the anode is generated,
iv) The amount of the reformed gas generated is equal to or higher than the minimum flow rate FrMin necessary for preventing the oxidative deterioration of the anode when the anode temperature of the solid oxide fuel cell is equal to or higher than the oxidative deterioration point.
FkE represents the flow rate of the hydrocarbon-based fuel supplied to the reformer in a state where all of the above are satisfied,
The flow rate of the hydrocarbon-based fuel that has been supplied to the reformer at the start of the stop method is expressed as Fk0,
When the calculated value of the flow rate of the hydrocarbon-based fuel that can be reformed by the type of reforming method performed after the start of the stopping method at the measured temperature of the reforming catalyst layer is expressed as FkCALC,
When the anode temperature falls below the oxidative degradation point, the supply of hydrocarbon fuel to the reformer is stopped and the stopping method is terminated.
While the anode temperature is not below the oxidation degradation point,
A) a step of measuring the reforming catalyst layer temperature T, calculating FkCALC using the measured temperature T, and comparing the values of FkCALC and FkE;
B) A step of sequentially performing the following steps B1 to B4 when FkCALC <FkE in step A,
B1) Step of heating the reforming catalyst layer
B2) a step of measuring the reforming catalyst layer temperature T, calculating FkCALC using the measured temperature T, and comparing the values of FkCALC and FkE;
B3) A step of returning to step B1 when FkCALC <FkE in step B2,
B4) When FkCALC ≧ FkE in step B2, the flow rate of the hydrocarbon-based fuel supplied to the reformer is changed from Fk0 to FkE, and the process proceeds to step D.
C) a step of sequentially performing the following steps C1 to C5 when FkCALC ≧ FkE in step A;
C1) Reforming catalyst layer temperature T is measured, and FkCALC and flow rate FkMinCALC of a hydrocarbon-based fuel capable of generating a reformed gas having a flow rate of FrMin in the reformer are calculated using the measured temperature T. And comparing the values of FkMinCALC and FkE,
C2) In step C1, when FkMinCALC ≧ FkE, the flow rate of the hydrocarbon-based fuel supplied to the reformer is set to FkE, and the process proceeds to step D.
C3) a step of comparing the values of FkMinCALC and FkCALC calculated in step C1 when FkMinCALC <FkE in step C1;
C4) In step C3, when FkCALC> FkMinCALC, the flow rate of the hydrocarbon-based fuel supplied to the reformer is changed to FkMINCALC, and the process returns to step C1.
C5) A step of sequentially performing the following steps C6 to C9 when FkCALC ≦ FkMinCALC in step C3,
C6) raising the temperature of the reforming catalyst layer;
C7) measuring the reforming catalyst layer temperature T, calculating FkCALC and FkMinCALC using the measured temperature T, and comparing the values of FkCALC and FkE;
C8) When FkCALC <FkE in step C7, the flow rate of the hydrocarbon-based fuel supplied to the reformer is set to FkMinCALC, and the process returns to step C6.
C9) Step F7, in which, when FkCALC ≧ FkE, the flow rate of the hydrocarbon-based fuel supplied to the reformer is set to FkE, and the process proceeds to Step D.
And D) A method for shutting down an indirect internal reforming solid oxide fuel cell is provided which comprises waiting for the anode temperature to fall below the oxidative degradation point.
図1に、本発明を実施することのできる間接内部改質型SOFCの一形態を模式的に示す。 [Indirect internal reforming SOFC]
FIG. 1 schematically shows an embodiment of an indirect internal reforming SOFC that can implement the present invention.
本明細書において、次の条件i~ivの全てが満たされている状態を改質停止可能状態と呼ぶ。
i)SOFCのアノード温度が定常である。
ii)前記アノード温度が酸化劣化点未満である。
iii)改質器において、炭化水素系燃料が改質され、アノードに供給するのに適した組成の改質ガスが生成している。
iv)この改質ガスの生成量が、SOFCのアノード温度が酸化劣化点以上の温度にある場合においてアノードの酸化劣化を防止するために必要最小限な流量FrMin以上である。 [Reforming stoppage possible state]
In this specification, a state in which all of the following conditions i to iv are satisfied is referred to as a reforming stoppable state.
i) The anode temperature of the SOFC is steady.
ii) The anode temperature is lower than the oxidation deterioration point.
iii) In the reformer, the hydrocarbon-based fuel is reformed, and a reformed gas having a composition suitable for supply to the anode is generated.
iv) The amount of the reformed gas generated is equal to or higher than the minimum flow rate FrMin necessary for preventing the oxidative deterioration of the anode when the anode temperature of the SOFC is equal to or higher than the oxidative deterioration point.
アノード温度は、アノード電極の温度を意味するが、アノード電極の温度を物理的に直接測定することが困難な場合には、アノード近傍のセパレータなどのスタック構成部材の温度とすることができる。アノード温度の測定位置は、安全制御の観点から相対的に温度が高くなる箇所、より好ましくは最も温度が高くなる箇所を採用することが好ましい。温度が高くなる位置は、予備実験やシミュレーションにより知ることができる。 <Conditions i and ii>
The anode temperature means the temperature of the anode electrode. When it is difficult to directly measure the temperature of the anode electrode directly, it can be the temperature of a stack component such as a separator in the vicinity of the anode. As the anode temperature measurement position, it is preferable to adopt a location where the temperature is relatively high, more preferably a location where the temperature is highest, from the viewpoint of safety control. The position where the temperature rises can be known through preliminary experiments and simulations.
条件iiiは、改質器において炭化水素系燃料が改質されており、アノードに供給するのに適した組成の改質ガスが得られている状態であることを意味している。例えば、炭化水素系燃料が炭素数2以上の炭化水素系燃料を含む場合、改質ガスが還元性であるとともに、改質ガス中のC2+成分(炭素数2以上の化合物)が炭素析出による流路閉塞やアノード劣化に対して問題にならない濃度以下である状態であることを意味している。このときのC2+成分の濃度は、改質ガス中の質量分率として50ppb以下が好ましい。 <Condition iii>
The condition iii means that the hydrocarbon-based fuel is reformed in the reformer and a reformed gas having a composition suitable for supplying to the anode is obtained. For example, when the hydrocarbon-based fuel contains a hydrocarbon-based fuel having 2 or more carbon atoms, the reformed gas is reducible, and the C2 + component (compound having 2 or more carbon atoms) in the reformed gas flows due to carbon deposition. This means that the concentration is below the concentration that does not cause a problem with respect to path blockage or anode deterioration. The concentration of the C2 + component at this time is preferably 50 ppb or less as a mass fraction in the reformed gas.
アノードの酸化劣化を防止するために必要最小限の改質ガス流量FrMinは、カソードオフガスのアノード出口からアノード内部への拡散によりアノード電極が酸化劣化しない流量のうち最も小さい流量である。この改質ガス流量は、アノード温度を酸化劣化点以上に保持した状態で、改質ガス流量を変えて実験やシミュレーションを行い、予め知っておくことができる。 <Condition iv>
The minimum necessary reformed gas flow rate FrMin for preventing oxidative deterioration of the anode is the smallest flow rate among the flow rates at which the anode electrode is not oxidatively deteriorated due to diffusion of the cathode off-gas from the anode outlet to the inside of the anode. This reformed gas flow rate can be known in advance by performing experiments and simulations by changing the reformed gas flow rate while maintaining the anode temperature at or above the oxidation deterioration point.
改質停止可能状態において改質器(特には改質触媒層)に供給される炭化水素系燃料の流量をFkEと表す。 <FkE>
The flow rate of the hydrocarbon-based fuel supplied to the reformer (particularly the reforming catalyst layer) in a state where the reforming can be stopped is represented as FkE.
停止方法開始時点で改質器に供給していた炭化水素系燃料の流量をFk0と表す。 [Fk0]
The flow rate of the hydrocarbon-based fuel that has been supplied to the reformer at the start of the stop method is represented as Fk0.
測定された改質触媒層温度において停止方法開始後に行う種類の改質法によって改質可能な炭化水素系燃料の流量(以下場合により、この流量を「改質可能流量」と称す。)の計算値をFkCALCと表す。つまり、FkCALCは、改質触媒層の温度を測定し、改質触媒層がその温度である場合に、改質触媒層で改質可能な炭化水素系燃料の流量を計算することによって求めることができる。このとき、改質触媒層では停止方法開始後に行なう種類の改質法を行なうものとする(以下場合により、改質法の種類を、改質タイプとよぶ。)。改質タイプは、例えば水蒸気改質、自己熱改質、部分酸化改質である。 [FkCALC]
Calculation of the flow rate of the hydrocarbon-based fuel that can be reformed by the type of reforming method performed after the stop method is started at the measured reforming catalyst layer temperature (hereinafter, this flow rate is referred to as “reformable flow rate”). The value is expressed as FkCALC. That is, FkCALC can be obtained by measuring the temperature of the reforming catalyst layer and calculating the flow rate of the hydrocarbon-based fuel that can be reformed by the reforming catalyst layer when the reforming catalyst layer is at that temperature. it can. At this time, the reforming catalyst layer is subjected to the kind of reforming method performed after the start of the stop method (hereinafter, the type of reforming method is referred to as the reforming type). The reforming type is, for example, steam reforming, autothermal reforming, or partial oxidation reforming.
測定された改質触媒層温度において停止方法開始後に行う種類の改質法によって流量がFrMinである改質ガスを改質器で生成可能な炭化水素系燃料の流量の計算値をFkMinCALCと表す。つまり、FkMinCALCは、改質触媒層の温度を測定し、改質触媒層がその温度である場合に、流量がFrMinである改質ガスを改質器で生成可能な炭化水素系燃料の流量を計算することによって求めることができる。このとき、改質触媒層では停止方法開始後に行なう種類の改質法を行なうものとする。 [FkMinCALC]
A calculated value of the flow rate of the hydrocarbon-based fuel that can generate the reformed gas having the flow rate of FrMin by the reformer of the kind that is performed after the stop method is started at the measured reforming catalyst layer temperature is represented as FkMinCALC. In other words, FkMinCALC measures the temperature of the reforming catalyst layer, and when the reforming catalyst layer is at that temperature, the flow rate of the hydrocarbon-based fuel that can generate the reformed gas whose flow rate is FrMin in the reformer. It can be obtained by calculating. At this time, the reforming catalyst layer is subjected to the kind of reforming method performed after the stop method is started.
停止方法開始前後で同じタイプの改質を行ってもよいが、異なるタイプの改質を行ってもよい。例えば、停止方法開始前に水蒸気改質を行い、停止方法を開始してからはオートサーマルリフォーミングを行うことができる。また、停止方法開始前に水蒸気改質を行い、停止方法を開始してからは部分酸化改質を行うことができる。 [When changing the reforming method before and after the start of the stopping method]
The same type of reforming may be performed before and after starting the stopping method, but different types of reforming may be performed. For example, steam reforming can be performed before the stop method is started, and autothermal reforming can be performed after the stop method is started. Further, steam reforming can be performed before the stop method is started, and partial oxidation reforming can be performed after the stop method is started.
FkCALCやFkMinCALCの算出には、改質触媒層温度の測定値を用いる。このために、改質触媒層温度を測定する。例えば、改質触媒層温度を監視する(継続して測定する)ことができる。 [Measurement of reforming catalyst layer temperature]
For the calculation of FkCALC and FkMINCALC, the measured value of the reforming catalyst layer temperature is used. For this purpose, the reforming catalyst layer temperature is measured. For example, the reforming catalyst layer temperature can be monitored (continuously measured).
本発明においては、アノード温度が酸化劣化点を下回っていない間に以下の工程A~Dを行なう。アノード温度が酸化劣化点を下回ったら、工程A~Dの実施状況にかかわらず、改質器への炭化水素系燃料の供給を停止し、停止方法を終了することができる。 [Steps included in the stopping method]
In the present invention, the following steps A to D are performed while the anode temperature is not lower than the oxidation deterioration point. When the anode temperature falls below the oxidative degradation point, the supply of hydrocarbon fuel to the reformer can be stopped and the stopping method can be terminated regardless of the implementation status of Steps A to D.
まず改質触媒層温度Tを測定する。そして、この温度Tに基づいて改質可能流量FkCALCを算出する。さらに、前述の改質停止可能状態における炭化水素系燃料の改質器への供給流量FkEと、このFkCALCとの大小関係を調べる。 [Process A]
First, the reforming catalyst layer temperature T is measured. Based on this temperature T, a reformable flow rate FkCALC is calculated. Further, the magnitude relationship between the supply flow rate FkE of the hydrocarbon-based fuel to the reformer in the above-described reforming stoppable state and the FkCALC is examined.
工程Aにおいて、FkCALC<FkEの場合、次の工程B1~B4を順次行なう。なお、「FkCALC<FkE」は、流量がFkEである炭化水素系燃料を、改質器において(改質タイプを変更する場合は変更後の改質タイプによって)改質できないことを意味しているとみなす。 [Process B]
In step A, if FkCALC <FkE, the following steps B1 to B4 are sequentially performed. Note that “FkCALC <FkE” means that a hydrocarbon fuel having a flow rate of FkE cannot be reformed in the reformer (by changing the reforming type when the reforming type is changed). It is considered.
まず工程B1を行なう。すなわち、改質触媒層を昇温する工程を行なう。 ・ Process B1
First, step B1 is performed. That is, a step of raising the temperature of the reforming catalyst layer is performed.
そして、工程B2を行なう。すなわち、改質触媒層温度Tを測定し、このTを用いてFkCALCを算出し、このFkCALCとFkEの値を比較する工程を行なう。 ・ Process B2
And process B2 is performed. That is, a step of measuring the reforming catalyst layer temperature T, calculating FkCALC using this T, and comparing the values of FkCALC and FkE is performed.
工程B2においてFkCALC<FkEの場合には、工程B1に戻る工程を行なう。つまり、FkCALC<FkEとなる間は、工程B1~B3を繰り返して行なう。この間に改質触媒層の温度は上昇してゆく。 ・ Process B3
If FkCALC <FkE in step B2, a step returning to step B1 is performed. That is, steps B1 to B3 are repeated while FkCALC <FkE. During this time, the temperature of the reforming catalyst layer rises.
工程B2においてFkCALC≧FkEの場合には、改質器に供給する炭化水素系燃料の流量(Fkと表す)をFk0からFkEにし、工程Dに移る工程を行なう。
「FkCALC≧FkE」は、流量がFkEである炭化水素系燃料を改質触媒層において(改質タイプを変更する場合は変更後の改質タイプによって)改質可能であることを意味するとみなす。 ・ Process B4
If FkCALC ≧ FkE in step B2, the flow rate of hydrocarbon-based fuel supplied to the reformer (represented as Fk) is changed from Fk0 to FkE, and the process proceeds to step D.
“FkCALC ≧ FkE” is considered to mean that a hydrocarbon-based fuel having a flow rate of FkE can be reformed in the reforming catalyst layer (depending on the reforming type after the change when the reforming type is changed).
工程Aにおいて、FkCALC≧FkEの場合、工程Cを行なう。なお、「FkCALC≧FkE」は、流量がFkEである炭化水素系燃料を、改質器において(停止方法開始前後で改質タイプを変更する場合は変更後の改質タイプによって)改質できることを意味しているとみなす。 [Process C]
In step A, when FkCALC ≧ FkE, step C is performed. “FkCALC ≧ FkE” means that a hydrocarbon fuel with a flow rate of FkE can be reformed in the reformer (by changing the reforming type when the reforming type is changed before and after the start of the stop method). Consider it to mean.
まず、改質触媒層温度Tを測定し、このTに基づいてFkMinCALCおよびFkCALCを算出し、このFkMinCALCとFkEの値を比較する。 ・ Process C1
First, the reforming catalyst layer temperature T is measured, FkMinCALC and FkCALC are calculated based on this T, and the values of FkMinCALC and FkE are compared.
工程C1において、FkMinCALC≧FkEの場合、改質器に供給する炭化水素系燃料の流量(Fk)をFkEにし、工程Dに移る工程を行なう。 ・ Process C2
In step C1, when FkMinCALC ≧ FkE, the flow rate of the hydrocarbon-based fuel supplied to the reformer (Fk) is set to FkE, and the step of moving to step D is performed.
工程C1においてFkMinCALC<FkEの場合には、工程C1で算出したFkMinCALCの値とFkCALCの値を比較する。 ・ Process C3
If FkMinCALC <FkE in step C1, the value of FkMinCALC calculated in step C1 is compared with the value of FkCALC.
工程C3において、FkCALC>FkMinCALCの場合に、改質器に供給する炭化水素系燃料の流量FkをFkMinCALCにし、工程C1に戻る。つまり、FkMinCALC<FkEかつFkCALC>FkMinCALCとなる間は、工程C1、C3およびC4を繰り返して行なう。 ・ Process C4
In step C3, when FkCALC> FkMinCALC, the flow rate Fk of the hydrocarbon-based fuel supplied to the reformer is set to FkMinCALC, and the process returns to step C1. That is, steps C1, C3, and C4 are repeated while FkMinCALC <FkE and FkCALC> FkMinCALC.
工程C3において、FkCALC≦FkMinCALCの場合に、工程C6~C9を順次行う。 ・ Process C5
In step C3, when FkCALC ≦ FkMinCALC, steps C6 to C9 are sequentially performed.
改質触媒層を昇温する。工程C6は、工程B1と同様にして行うことができる。 ・ Process C6
The temperature of the reforming catalyst layer is raised. Step C6 can be performed in the same manner as Step B1.
改質触媒層温度Tを測定し、この測定温度Tを用いてFkCALCおよびFkMinCALCを算出し、このFkCALCの値とFkEの値とを比較する。 ・ Process C7
The reforming catalyst layer temperature T is measured, FkCALC and FkMinCALC are calculated using the measured temperature T, and the FkCALC value is compared with the FkE value.
工程C7において、FkCALK<FkEの場合に、改質器に供給する炭化水素系燃料の流量FkをFkMinCALC(工程C7で求めた値)にし、工程C6に戻る。 ・ Process C8
In step C7, when FkCALK <FkE, the flow rate Fk of the hydrocarbon-based fuel supplied to the reformer is set to FkMinCALC (the value obtained in step C7), and the process returns to step C6.
工程7において、FkCALK≧FkEの場合に、改質器に供給する炭化水素系燃料の流量FkをFkEにし、工程Dに移る。 ・ Process C9
In
工程Dでは、アノード温度が、酸化劣化点を下回るのを待つ。この間、炭化水素系燃料の流量はFkEに維持し、改質器に供給する水蒸気改質もしくは自己熱改質用の水(スチームを含む)流量、自己熱改質または部分酸化改質用の空気流量、カソード空気流量、バーナーに供給する燃料および空気流量、熱交換器に供給する水や空気などの流体の流量などの、間接内部改質型SOFCに供給する流体の流量、改質器および水や液体燃料の蒸発器、セルスタック、流体の供給配管などを加熱するための電気ヒータ出力、熱電変換モジュールなどから取り出される電気入力などの、間接内部改質型SOFCへの電気の入出力を、予め定めた改質停止可能状態における操作条件に維持することができる。すなわち、予め定めた改質停止可能状態における間接内部改質型SOFCの操作条件に維持することができる。アノード温度は時間とともに低下していくので、いずれアノード温度が酸化劣化点を下回る。熱電対等の温度センサーを用いて、アノード温度を適宜監視する(継続して測定する)ことができる。 [Process D]
In step D, the process waits for the anode temperature to fall below the oxidation deterioration point. During this time, the flow rate of the hydrocarbon fuel is maintained at FkE, the flow rate of water for steam reforming or autothermal reforming (including steam) supplied to the reformer, air for autothermal reforming or partial oxidation reforming. The flow rate of the fluid supplied to the indirect internal reforming SOFC, such as the flow rate, the cathode air flow rate, the fuel and air flow rate supplied to the burner, the flow rate of the fluid such as water and air supplied to the heat exchanger, the reformer and water Input and output of electricity to the indirect internal reforming SOFC, such as an electric heater output for heating an evaporator of liquid fuel, a cell stack, a fluid supply pipe, etc., an electric input taken from a thermoelectric conversion module, etc. It is possible to maintain the operation conditions in a predetermined reforming stoppable state. That is, it is possible to maintain the operation conditions of the indirect internal reforming SOFC in a predetermined reforming stoppable state. Since the anode temperature decreases with time, the anode temperature eventually falls below the oxidation degradation point. The anode temperature can be appropriately monitored (continuously measured) using a temperature sensor such as a thermocouple.
図2を用いて、本発明の停止方法の一例を説明する。図2(a)~(c)において、横軸は本発明の停止方法を開始した時点からの経過時間である。同図(a)において縦軸は改質器から得られる改質ガスの流量であり、(b)において縦軸は温度であり、(c)において縦軸は、炭化水素燃料の流量(改質器に供給する炭化水素系燃料の流量Fk、計算されたFkCALCおよびFkMinCALC)である(図3~5においても同様である)。 [Case 1]
An example of the stopping method of the present invention will be described with reference to FIG. 2 (a) to 2 (c), the horizontal axis represents the elapsed time from the start of the stopping method of the present invention. In (a), the vertical axis represents the flow rate of reformed gas obtained from the reformer, in (b) the vertical axis represents temperature, and in (c), the vertical axis represents the flow rate of hydrocarbon fuel (reformation). The flow rate Fk of hydrocarbon-based fuel supplied to the vessel, the calculated FkCALC and FkMINCALC) (the same applies to FIGS. 3 to 5).
上記ケースでは、FkMinCALCがFkE以上となるより早く、FkCALCがFkMinCALC以下となるため、工程C7においてFkCALCがFkE以上となった時点で、FkをFkEにする(工程C9)。本ケースでは、FkCALCがFkMinCALC以下となるより早く、FkMinCALCがFkE以上となるため、工程C1においてFkMinCALCがFkE以上となった時点で、FkをFkEにする(工程C2)。図3を用いて、このケースについて説明する。 [Case 2]
In the above case, FkCALC becomes FkMINCALC or less earlier than FkMinCALC becomes FkE or more. Therefore, when FkCALC becomes FkE or more in Step C7, Fk is set to FkE (Step C9). In this case, since FkCALC becomes FkE or more sooner than FkCALC becomes FkMINCALC or less, Fk becomes FkE when FkMINCALC becomes FkE or more in Step C1 (Step C2). This case will be described with reference to FIG.
ケース1では、工程C7においてFkCALCがFkE以上となった時点で、Fkを直ちにFkEにする(工程C9)。本ケースでは、工程C9において、FkからFkEへの流量増加を徐々に、特には段階的に、行なう。図4を用いて、このケースについて説明する。図7には、Fkを徐々にFkEにする手順をフローチャートの形で示す。 [Case 3]
In
図5を用いて、工程Aで算出したFkCALCが、改質停止可能状態において改質器に供給される炭化水素系燃料の流量FkEより小さい場合、すなわちFkCALC<FkEの場合について説明する。つまり、工程Bを行なう場合について説明する。 [Case 4]
The case where FkCALC calculated in step A is smaller than the flow rate FkE of the hydrocarbon-based fuel supplied to the reformer in the state where reforming can be stopped, that is, the case of FkCALC <FkE will be described using FIG. That is, the case where the process B is performed will be described.
本明細書において、改質触媒層においてある流量の炭化水素系燃料が改質可能であるとは、その流量の炭化水素系燃料を改質触媒層に供給した場合に、改質触媒層から排出されるガスの組成が、SOFCのアノードに供給するに適した組成になることをいう。 [About “reformable”]
In this specification, that a hydrocarbon-based fuel at a certain flow rate in the reforming catalyst layer can be reformed means that when the hydrocarbon-based fuel at that flow rate is supplied to the reforming catalyst layer, it is discharged from the reforming catalyst layer. The composition of the gas to be used is a composition suitable for supplying to the anode of the SOFC.
以下、測定された改質触媒層の温度に基づいて、改質触媒層において改質可能な炭化水素系燃料の流量を算出する方法に関して説明する。 [Calculation of FkCALC]
Hereinafter, a method for calculating the flow rate of the hydrocarbon-based fuel that can be reformed in the reforming catalyst layer based on the measured temperature of the reforming catalyst layer will be described.
以下、測定された改質触媒層の温度に基づいて、改質触媒層において流量がFrMinである改質ガスを改質器で生成可能な炭化水素系燃料の流量FkMinCALCを算出する方法に関して説明する。 [Calculation of FkMinCALC]
Hereinafter, a method for calculating the flow rate FkMinCALC of the hydrocarbon-based fuel that can generate the reformed gas having the flow rate of FrMin in the reforming catalyst layer in the reformer based on the measured temperature of the reforming catalyst layer will be described. .
以下、改質触媒層温度の測定個所について詳述する。この測定個所は、FkCALCを知るための予備実験や、工程A~Cにおいて改質触媒層の温度を測定する際、に採用できる。 [Measurement point of reforming catalyst layer temperature]
Hereinafter, measurement points of the reforming catalyst layer temperature will be described in detail. This measurement point can be used in preliminary experiments for knowing FkCALC and when measuring the temperature of the reforming catalyst layer in steps A to C.
・温度測定個所
改質触媒層の温度測定点が一点である場合、温度の測定個所としては、安全側制御の観点から、好ましくは改質触媒層の中で相対的に温度が低くなる箇所、より好ましくは改質触媒層の中で最も温度が低くなる個所を採用することが好ましい。改質触媒層における反応熱が吸熱である場合、温度測定個所として、触媒層中心付近を選ぶことができる。改質触媒層における反応熱が発熱であり、放熱によって中心部より端部の方が低温になる場合、温度測定個所として、触媒層端部を選ぶことができる。温度が低くなる位置は、予備実験やシミュレーションにより知ることができる。 <When there is one temperature measurement point>
-Temperature measurement location When the temperature measurement point of the reforming catalyst layer is one point, the temperature measurement location is preferably a location where the temperature is relatively low in the reforming catalyst layer, from the viewpoint of safety side control, More preferably, it is preferable to employ a portion having the lowest temperature in the reforming catalyst layer. When the heat of reaction in the reforming catalyst layer is endothermic, the vicinity of the center of the catalyst layer can be selected as the temperature measurement location. When the heat of reaction in the reforming catalyst layer is exothermic, and the end portion becomes cooler than the center portion due to heat dissipation, the end portion of the catalyst layer can be selected as the temperature measurement location. The position where the temperature is lowered can be known by preliminary experiments and simulations.
温度の測定点は一点である必要はない。より正確な制御の観点から、温度測定点が2点以上であることが好ましい。例えば、改質触媒層の入口温度と出口温度を測定し、これらを平均した温度を前述の改質触媒層温度Tとすることができる。ただし、改質触媒層に供給する炭化水素系燃料(原燃料)の減少を伴う反応以外の反応速度が原燃料の減少を伴う反応より非常に速く、原燃料以外の成分が瞬時に平衡組成に到達するとみなせる場合は、改質触媒層の温度測定点が複数ある場合でも、工程CにおいてFkMinCALCを算出する温度としては、その複数点で測定された温度のうちの、改質触媒層出口に最も近い温度を用いるのが好ましい。改質触媒層出口に最も近い温度が複数点ある場合には、それらのうちの最低値やそれらの平均値など、適宜計算した値を代表値とすることができる。 <When there are multiple temperature measurement points>
The temperature measurement point need not be a single point. From the viewpoint of more accurate control, it is preferable that there are two or more temperature measurement points. For example, the inlet temperature and outlet temperature of the reforming catalyst layer are measured, and the average of these can be used as the aforementioned reforming catalyst layer temperature T. However, the reaction rate other than the reaction accompanied by a decrease in the hydrocarbon fuel (raw fuel) supplied to the reforming catalyst layer is much faster than the reaction accompanied by the decrease in the raw fuel, and components other than the raw fuel instantaneously have an equilibrium composition. In the case where there are a plurality of temperature measurement points of the reforming catalyst layer, the temperature at which FkMinCALC is calculated in Step C is the highest at the reforming catalyst layer outlet among the temperatures measured at the plurality of points. It is preferable to use close temperatures. In the case where there are a plurality of temperatures closest to the reforming catalyst layer outlet, appropriately calculated values such as the lowest value and the average value thereof can be used as representative values.
全ての分割領域の温度を知るために、次のような個所の温度を計測することができる。
・各分割領域の入口および出口。
・各分割領域内部(入口および出口より内側)(1点もしくは複数点)。
・各分割領域の入口、出口および内部(一つの分割領域について1点もしくは複数点)。 (Example of temperature measurement location)
In order to know the temperature of all the divided areas, the temperature of the following points can be measured.
-Entrance and exit of each divided area.
-Inside each divided area (inside from the entrance and exit) (one or more points).
-Entrance, exit and inside of each divided area (one or more points for one divided area).
・一部の分割領域の入口および出口。
・一部の分割領域内部(入口および出口より内側)(1点もしくは複数点)。
・一部の分割領域の入口、出口および内部(一つの分割領域について1点もしくは複数点)。 In order to know the temperature of some of the divided regions, the temperature at the following locations can be measured.
-Entrance and exit of some divided areas.
-Inside of some divided areas (inside from the inlet and outlet) (one or more points).
-Entrances, exits, and interiors of some divided areas (one or more points for one divided area).
炭化水素系燃料の流量FkをFkEにする際に、必要に応じ、これにあわせて改質器に供給する水蒸気改質または自己熱改質用の水(スチームを含む)流量、自己熱改質または部分酸化改質用の空気流量、カソード空気流量、バーナーに供給する燃料および空気流量、熱交換器に供給する水や空気などの流体の流量などの、間接内部改質型SOFCに供給する流体の流量、改質器および水や液体燃料の蒸発器、セルスタック、流体の供給配管などを加熱するための電気ヒータ出力、熱電変換モジュールなどから取り出される電気入力などの、間接内部改質型SOFCへの電気の入出力を、予め定めた改質停止可能状態における操作条件にすることができる。すなわち、予め定めた改質停止可能状態における間接内部改質型SOFCの操作条件に設定することができる。 [Operating conditions other than hydrocarbon fuel flow rate]
When the flow rate Fk of hydrocarbon-based fuel is set to FkE, the flow rate of water for steam reforming or autothermal reforming (including steam) supplied to the reformer according to the flow rate, if necessary, self-thermal reforming Or the fluid supplied to the indirect internal reforming SOFC, such as the air flow rate for partial oxidation reforming, the cathode air flow rate, the fuel and air flow rate supplied to the burner, the flow rate of fluid such as water or air supplied to the heat exchanger Indirect internal reforming SOFC, such as the flow rate of air, the reformer and the electric heater output to heat the water and liquid fuel evaporator, cell stack, fluid supply piping, etc., the thermoelectric conversion module etc. The input / output of electricity to can be set to a predetermined operating condition in a state where reforming can be stopped. That is, it is possible to set the operation condition of the indirect internal reforming SOFC in a predetermined reforming stoppable state.
水蒸気改質反応を行う場合、つまり水蒸気改質もしくはオートサーマルリフォーミングを行う場合には、改質触媒層にスチームを供給する。部分酸化改質反応を行う場合、つまり部分酸化改質もしくはオートサーマルリフォーミングを行う場合には、改質触媒層に酸素含有ガスを供給する。酸素含有ガスとしては、酸素を含有するガスを適宜用いることができるが、入手容易性から空気が好ましい。 [Others]
When a steam reforming reaction is performed, that is, when steam reforming or autothermal reforming is performed, steam is supplied to the reforming catalyst layer. When performing a partial oxidation reforming reaction, that is, when performing partial oxidation reforming or autothermal reforming, an oxygen-containing gas is supplied to the reforming catalyst layer. As the oxygen-containing gas, a gas containing oxygen can be used as appropriate, but air is preferable because it is easily available.
炭化水素系燃料としては、改質ガスの原料としてSOFCの分野で公知の、分子中に炭素と水素を含む(酸素など他の元素を含んでもよい)化合物もしくはその混合物から適宜選んで用いることができ、炭化水素類、アルコール類など分子中に炭素と水素を有する化合物を用いることができる。例えばメタン、エタン、プロパン、ブタン、天然ガス、LPG(液化石油ガス)、都市ガス、ガソリン、ナフサ、灯油、軽油等の炭化水素燃料、また、メタノール、エタノール等のアルコール、ジメチルエーテル等のエーテル等である。 [Hydrocarbon fuel]
As the hydrocarbon-based fuel, as a reformed gas raw material, a compound known from the field of SOFC, containing carbon and hydrogen (may contain other elements such as oxygen) or a mixture thereof, or a mixture thereof may be used as appropriate. And compounds having carbon and hydrogen in the molecule such as hydrocarbons and alcohols can be used. For example, hydrocarbon fuel such as methane, ethane, propane, butane, natural gas, LPG (liquefied petroleum gas), city gas, gasoline, naphtha, kerosene, light oil, etc., alcohol such as methanol and ethanol, ether such as dimethyl ether, etc. is there.
改質器は、炭化水素系燃料から水素を含む改質ガスを製造する。 [Reformer]
The reformer produces a reformed gas containing hydrogen from a hydrocarbon fuel.
改質器から得られる改質ガスが、SOFCのアノードに供給される。一方、SOFCのカソードには空気などの酸素含有ガスが供給される。発電時には、発電に伴いSOFCが発熱し、その熱がSOFCから改質器へと、輻射伝熱などにより伝わる。こうしてSOFC排熱が改質器を加熱するために利用される。ガスの取り合い等は適宜配管等を用いて行う。 [SOFC]
The reformed gas obtained from the reformer is supplied to the anode of the SOFC. On the other hand, an oxygen-containing gas such as air is supplied to the cathode of the SOFC. During power generation, the SOFC generates heat with power generation, and the heat is transmitted from the SOFC to the reformer by radiant heat transfer or the like. Thus, the SOFC exhaust heat is used to heat the reformer. Gas exchange and the like are appropriately performed using piping or the like.
筐体(モジュール容器)としては、SOFC、改質器および燃焼領域を収容可能な適宜の容器を用いることができる。その材料としては、例えばステンレス鋼など、使用する環境に耐性を有する適宜の材料を用いることができる。容器には、ガスの取り合い等のために、適宜接続口が設けられる。 [Case]
As the casing (module container), an appropriate container capable of accommodating the SOFC, the reformer, and the combustion region can be used. As the material, for example, an appropriate material having resistance to the environment to be used, such as stainless steel, can be used. The container is appropriately provided with a connection port for gas exchange and the like.
燃焼領域は、SOFCのアノードから排出されるアノードオフガスを燃焼可能な領域である。例えば、アノード出口を筐体内に開放し、アノード出口近傍の空間を燃焼領域とすることができる。酸素含有ガスとして例えばカソードオフガスを用いてこの燃焼を行なうことができる。このために、カソード出口を筐体内に開放することができる。 (Combustion area)
The combustion region is a region where the anode off gas discharged from the anode of the SOFC can be combusted. For example, the anode outlet can be opened in the housing, and the space near the anode outlet can be used as a combustion region. This combustion can be performed using, for example, a cathode off gas as the oxygen-containing gas. For this purpose, the cathode outlet can be opened in the housing.
改質器で用いる水蒸気改質触媒、部分酸化改質触媒、自己熱改質触媒のいずれも、それぞれ公知の触媒を用いることができる。水蒸気改質触媒の例としてはルテニウム系およびニッケル系触媒、部分酸化改質触媒の例としては白金系触媒、自己熱改質触媒の例としてはロジウム系触媒を挙げることができる。水蒸気改質を行う場合には、水蒸気改質機能を持つ自己熱改質触媒を用いることもできる。 [Reforming catalyst]
Any of the steam reforming catalyst, partial oxidation reforming catalyst, and autothermal reforming catalyst used in the reformer can be a known catalyst. Examples of the steam reforming catalyst include ruthenium-based and nickel-based catalysts, examples of the partial oxidation reforming catalyst include platinum-based catalysts, and examples of the autothermal reforming catalyst include rhodium-based catalysts. When steam reforming is performed, a self-thermal reforming catalyst having a steam reforming function can also be used.
以下、水蒸気改質、自己熱改質、部分酸化改質のそれぞれにつき、改質器における停止運転時の条件について説明する。 [Operation conditions of reformer]
Hereinafter, the conditions at the time of stop operation in the reformer will be described for each of steam reforming, autothermal reforming, and partial oxidation reforming.
間接内部改質型SOFCの公知の構成要素は、必要に応じて適宜設けることができる。具体例を挙げれば、液体を気化させる気化器、各種流体を加圧するためのポンプ、圧縮機、ブロワなどの昇圧手段、流体の流量を調節するため、あるいは流体の流れを遮断/切り替えるためのバルブ等の流量調節手段や流路遮断/切り替え手段、熱交換・熱回収を行うための熱交換器、気体を凝縮する凝縮器、スチームなどで各種機器を外熱する加熱/保温手段、炭化水素系燃料(改質原料)や燃焼用燃料の貯蔵手段、計装用の空気や電気系統、制御用の信号系統、制御装置、出力用や動力用の電気系統、燃料中の硫黄分濃度を低減する脱硫器などである。 [Other equipment]
Known components of the indirect internal reforming SOFC can be appropriately provided as necessary. Specific examples include a vaporizer for vaporizing liquid, a pump for pressurizing various fluids, a pressure increasing means such as a compressor and a blower, a valve for adjusting the flow rate of the fluid, or for blocking / switching the flow of the fluid. Such as flow control means, flow path blocking / switching means, heat exchanger for heat exchange / recovery, condenser for condensing gas, heating / heat-retaining means for externally heating various devices with steam, etc., hydrocarbon system Fuel (reforming raw material) and combustion fuel storage means, instrumentation air and electrical system, control signal system, control device, output and power electrical system, desulfurization to reduce the concentration of sulfur in the fuel Such as a vessel.
2 水気化器に付設された電気ヒータ
3 改質器
4 改質触媒層
5 燃焼領域
6 SOFC
7 イグナイター
8 筐体(モジュール容器)
9 改質器に付設された電気ヒータ DESCRIPTION OF
7
9 Electric heater attached to the reformer
Claims (3)
- 炭化水素系燃料を改質して改質ガスを製造する、改質触媒層を有する改質器と、
該改質ガスを用いて発電を行う固体酸化物形燃料電池と、
該固体酸化物燃料電池から排出されるアノードオフガスを燃焼させる燃焼領域と、
該改質器、固体酸化物形燃料電池および燃焼領域を収容する筐体と、を有する間接内部改質型固体酸化物形燃料電池の停止方法であって、
次の条件iからiv、
i)該固体酸化物燃料電池のアノード温度が定常であり、
ii)該アノード温度が酸化劣化点未満であり、
iii)改質器において、炭化水素系燃料が改質され、アノードに供給するのに適した組成の改質ガスが生成しており、
iv)前記改質ガスの生成量が、該固体酸化物燃料電池のアノード温度が酸化劣化点以上の温度にある場合においてアノードの酸化劣化を防止するために必要最小限な流量FrMin以上である、
が全て満たされる状態において改質器に供給される炭化水素系燃料の流量をFkEと表し、
停止方法開始時点で改質器に供給していた炭化水素系燃料の流量をFk0と表し、
測定された改質触媒層の温度において、停止方法開始後に行う種類の改質法により改質可能な炭化水素系燃料の流量の計算値をFkCALCと表したとき、
アノード温度が酸化劣化点を下回ったら改質器への炭化水素系燃料の供給を停止して該停止方法を終了し、
アノード温度が酸化劣化点を下回っていない間に以下の工程、
A)改質触媒層温度Tを測定し、この測定温度Tを用いてFkCALCを算出し、このFkCALCとFkEの値を比較する工程、
B)工程AにおいてFkCALC<FkEの場合に、次の工程B1~B4を順次行なう工程、
B1)改質触媒層を昇温する工程、
B2)改質触媒層温度Tを測定し、この測定温度Tを用いてFkCALCを算出し、このFkCALCとFkEの値を比較する工程、
B3)工程B2においてFkCALC<FkEの場合に、工程B1に戻る工程、
B4)工程B2においてFkCALC≧FkEの場合に、改質器に供給する炭化水素系燃料の流量をFk0からFkEにし、工程Dに移る工程、
C)工程AにおいてFkCALC≧FkEの場合に、次の工程C1~C5を順次行なう工程、
C1)改質触媒層温度Tを測定し、この測定温度Tを用いて、FkCALCと、流量がFrMinである改質ガスを改質器で生成可能な炭化水素系燃料の流量FkMinCALCと、を算出し、このFkMinCALCとFkEとの値を比較する工程、
C2)工程C1において、FkMinCALC≧FkEの場合に、改質器に供給する炭化水素系燃料の流量をFkEにし、工程Dに移る工程、
C3)工程C1においてFkMinCALC<FkEの場合に、工程C1で算出したFkMinCALCとFkCALCとの値を比較する工程、
C4)工程C3において、FkCALC>FkMinCALCの場合に、改質器に供給する炭化水素系燃料の流量をFkMinCALCにし、工程C1に戻る工程、
C5)工程C3において、FkCALC≦FkMinCALCの場合に、次の工程C6~C9を順次行う工程、
C6)改質触媒層を昇温する工程、
C7)改質触媒層温度Tを測定し、この測定温度Tを用いてFkCALCおよびFkMinCALCを算出し、このFkCALCとFkEの値を比較する工程、
C8)工程C7においてFkCALC<FkEの場合に、改質器に供給する炭化水素系燃料の流量をFkMinCALCにし、工程C6に戻る工程、
C9)工程C7においてFkCALC≧FkEの場合に、改質器に供給する炭化水素系燃料の流量をFkEにし、工程Dに移る工程、
および
D)アノード温度が、酸化劣化点を下回るのを待つ工程
を有する間接内部改質型固体酸化物形燃料電池の停止方法。 A reformer having a reforming catalyst layer for reforming hydrocarbon fuel to produce reformed gas;
A solid oxide fuel cell that generates electric power using the reformed gas; and
A combustion region for burning anode off-gas discharged from the solid oxide fuel cell;
A method for stopping an indirect internal reforming solid oxide fuel cell comprising: a reformer, a solid oxide fuel cell, and a housing that houses a combustion region;
The following conditions i to iv,
i) The anode temperature of the solid oxide fuel cell is steady,
ii) the anode temperature is below the oxidative degradation point;
iii) In the reformer, the hydrocarbon-based fuel is reformed, and a reformed gas having a composition suitable for supplying to the anode is generated,
iv) The amount of the reformed gas generated is equal to or higher than the minimum flow rate FrMin necessary for preventing the oxidative deterioration of the anode when the anode temperature of the solid oxide fuel cell is equal to or higher than the oxidative deterioration point.
FkE represents the flow rate of the hydrocarbon-based fuel supplied to the reformer in a state where all of the above are satisfied,
The flow rate of the hydrocarbon-based fuel that has been supplied to the reformer at the start of the stop method is expressed as Fk0,
When the calculated value of the flow rate of the hydrocarbon-based fuel that can be reformed by the type of reforming method performed after the start of the stopping method at the measured temperature of the reforming catalyst layer is expressed as FkCALC,
When the anode temperature falls below the oxidative degradation point, the supply of hydrocarbon fuel to the reformer is stopped and the stopping method is terminated.
While the anode temperature is not below the oxidation degradation point,
A) a step of measuring the reforming catalyst layer temperature T, calculating FkCALC using the measured temperature T, and comparing the values of FkCALC and FkE;
B) A step of sequentially performing the following steps B1 to B4 when FkCALC <FkE in step A,
B1) Step of heating the reforming catalyst layer
B2) a step of measuring the reforming catalyst layer temperature T, calculating FkCALC using the measured temperature T, and comparing the values of FkCALC and FkE;
B3) A step of returning to step B1 when FkCALC <FkE in step B2,
B4) When FkCALC ≧ FkE in step B2, the flow rate of the hydrocarbon-based fuel supplied to the reformer is changed from Fk0 to FkE, and the process proceeds to step D.
C) a step of sequentially performing the following steps C1 to C5 when FkCALC ≧ FkE in step A;
C1) Reforming catalyst layer temperature T is measured, and FkCALC and flow rate FkMinCALC of a hydrocarbon-based fuel capable of generating a reformed gas having a flow rate of FrMin in the reformer are calculated using the measured temperature T. And comparing the values of FkMinCALC and FkE,
C2) In step C1, when FkMinCALC ≧ FkE, the flow rate of the hydrocarbon-based fuel supplied to the reformer is set to FkE, and the process proceeds to step D.
C3) a step of comparing the values of FkMinCALC and FkCALC calculated in step C1 when FkMinCALC <FkE in step C1;
C4) In step C3, when FkCALC> FkMinCALC, the flow rate of the hydrocarbon-based fuel supplied to the reformer is changed to FkMINCALC, and the process returns to step C1.
C5) A step of sequentially performing the following steps C6 to C9 when FkCALC ≦ FkMinCALC in step C3,
C6) raising the temperature of the reforming catalyst layer;
C7) measuring the reforming catalyst layer temperature T, calculating FkCALC and FkMinCALC using the measured temperature T, and comparing the values of FkCALC and FkE;
C8) When FkCALC <FkE in step C7, the flow rate of the hydrocarbon-based fuel supplied to the reformer is set to FkMinCALC, and the process returns to step C6.
C9) Step F7, in which, when FkCALC ≧ FkE, the flow rate of the hydrocarbon-based fuel supplied to the reformer is set to FkE, and the process proceeds to Step D.
And D) A method for shutting down an indirect internal reforming solid oxide fuel cell comprising waiting for the anode temperature to fall below the oxidation degradation point. - 前記炭化水素系燃料が、炭素数が2以上の炭化水素系燃料を含む請求項1記載の方法。 The method according to claim 1, wherein the hydrocarbon fuel includes a hydrocarbon fuel having 2 or more carbon atoms.
- 前記改質ガス中の、炭素数2以上の化合物の濃度が、質量基準で50ppb以下である請求項2記載の方法。 The method according to claim 2, wherein the concentration of the compound having 2 or more carbon atoms in the reformed gas is 50 ppb or less on a mass basis.
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CN201080052710.9A CN102742058B (en) | 2009-11-24 | 2010-11-22 | Method for stopping indirect internal reforming type solid oxide fuel cell |
CA2781506A CA2781506A1 (en) | 2009-11-24 | 2010-11-22 | Method for shutting down indirect internal reforming solid oxide fuel cell |
US13/511,251 US8790837B2 (en) | 2009-11-24 | 2010-11-22 | Method for shutting down indirect internal reforming solid oxide fuel cell |
KR1020127015350A KR20120129874A (en) | 2009-11-24 | 2010-11-22 | Method for stopping indirect internal reforming type solid oxide fuel cell |
EP10833166A EP2506354A1 (en) | 2009-11-24 | 2010-11-22 | Method for stopping indirect internal reforming type solid oxide fuel cell |
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JP2016040217A (en) * | 2014-08-13 | 2016-03-24 | Jx日鉱日石エネルギー株式会社 | Dehydrogenation system, and operating method of dehydrogenation system |
US10439237B2 (en) * | 2015-12-15 | 2019-10-08 | Nissan Motor Co., Ltd. | Fuel cell system and control of collector and burner when stopped |
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US20130011759A1 (en) | 2013-01-10 |
EP2506354A1 (en) | 2012-10-03 |
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US8790837B2 (en) | 2014-07-29 |
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